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<html lang="en">
<head>
	<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
	<title>变量</title>
	<script type="text/javascript">
		/*	var1 =40+40;
			var2 =var1*5;
			alert(var2);

			var var1;
			var1="是咖啡咖啡机卡";
			alert(var1)

			var name="广东",dianhua="8866754",shi="陆丰";
			alert(shi);

			var xingm="飒飒大师"

			var 不存在="不存在？";
			alert(不存在);*/


			/*累加(先自增，再运行)*/ 
			var1 = 8;
			var1 = ++var1;    
			alert(var1);


			/*累加(先运行，再自增) */
			var1 = 8;
			var1 = var1++;
			alert(var1);


			var1 = 10;
			var1 = --var1;
			alert(var1);


			var1 = 10;
			var1 = var1--;
			alert(var1);


			var no="没什么";
			alert(typeof no);
			alert(typeof 123.1);
			alert(typeof true);

			var str = '1+2';
			alert(eval(sta));


	</script>
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<body>
	
</body>
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